When I’m 164: How Can Bioscience Push the Limits of Lifespan?
In 1835, Charles Darwin reached the Galapagos Islands aboard the HMS Beagle. While there, someone (possibly Darwin) captured a tortoise named Harriet. She lived for 176 years, finally dying in 2006.
Other organisms in nature are known to live considerably longer than Harriet. These include the Methuselah tree, a bristlecone pine in Southern California that, at 4,843 years old, is perhaps the oldest known complex organism on Earth. Other creatures that age very slowly and live up to hundreds of years, showing little signs of senescence (aging), include rockfish, clams, lobsters and jellyfish.
Humans, too, live a long time compared to most species. The longest-living primates other than humans are our closest relatives in evolution, chimpanzees. They have an average life span of 53 years. This makes the current life expectancy in the West of nearly 80 years, with a maximum life span of 120 or so. Quite long, though not in the same league as Harriet the tortoise or bristlecone pine trees.
As scientists make new breakthroughs in understanding the mechanics of aging, the upper limits of aging might be changing for Homo sapiens. Already, life expectancy has increased dramatically since the late nineteenth century, when it was 40 for males and 42 for females at birth, and age 58 and 59 respectively if they survived to age 10 (infant mortality was much higher in 1890).
Life expectancy is expected to keep rising to perhaps age 100 sometime in the 22nd century, according to the United Nations. This comes from better hygiene and nutrition, and also from bio-med breakthroughs that range from antibiotics to targeted therapies for cancer and robotic surgery.
Is it possible that new waves of discoveries might take us on a path of even more dramatic increases in life extension?
Until recently, mainstream scientists would have answered with an emphatic no, suggesting that this was a fantasy offered up by alchemists, charlatans, and pseudo-scientists. Two trends have shifted this point of view.